Apparatus for converting formates into oxalates



Feb.1 3,1923. l 1,445,162.

H. W. PAULUS.

APPARATUS FOR CKONVERTING FORMATES INTO OXALATES.

FILED luLY 25,1920. 3 SHEETS SAEM z.

BISHEETS-`ISHEET 3- H. W. PAU-LUS. APPARATUS FOR CONVERTING FORMATES INTO OXALATES. F!LED JULY 26, 1920.

Feb. 13, 1923.

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MW//MM/W/WWW 'Patented Feb.y 13, 1923.

UNITED STATES HERMAN W. PAULUS, OF RICHMOND HILL,

NEW YORK, -ASSIGNOR TO ROYAL BAKING POWDER COMPANY, A CORPORATION OF NEW JERSEY.

APPARATUS FOR CONVERTING FORISIATES INTO OXALA-TES.

Application filed July 26.

To (1U ullomif may concern Be it known that I, HERMAN lV. Pxila's. a. citizen of the Ilnited States. and a resident of Richmond Hill. inthe county of Queens and State of New York. have invented certain new and useful lmprovements in Apparatus for Converting Forlmates into ()xalates. of which the following is a specification.

The present invention relates to an apparatus for converting formates into oxalates. and more particularly to an apparatus for convert-ing alkaline formates into alkaline oxalates.

lt has long been recognized that it is difficult economically to produce oxalates from foi-mates on a commercial scale. The experiments seeking to increase the quantity of production and decrease the cost of pro-- duction have covered a long series of vears and involved the expenditure of much effort and capital. Heretofore these experiments have been more or less unsuccessful with the result thatthe cost of oxalates is still relatively high. The object of the present invention is to produce an apparatus for converting formates into oxalates b v w.hich the oxalates may be produced quantitative-*ly and at a relatively low cost. The conditions under which foi-mates may be converted into oxalates are well recognized. 'hen the formate is subjected to a temperature ranging. from 3G00 to 4400 a molecule of hydrogen is driven ofl' in accordance with the following formula `(sodium formate is taken to illustrate the reaction) :l

ericogxazcgoagafng Up to 220 C. the formate is stable. Subjected to a temperature ranging between 220 C. and 360 C.. the formate is converted into a carbonate. lf the formate is subjected to atemperature exceeding 440 C.. the formate will pass through the oxalate state and be converted into carbonate exclusively.

lVith these conditions governing the production of oxalates from formates,l it has been proposed to carry on the conversion in closed vessels. This has been found dangerous unless an inert gas is nsed for displacing the hydrogen evolved so as to avoid explosions. It has also been proposed to 1920. Serial No. 399,085.

introduce the formatcinto a receptacle previously heated to aboutflOOO C. and maintain the receptacle at that temperature. This method has been found commerciallyv unsatisfactory becauseof the low percentage of formate resulting therefrom. Other methods of converting foi-mates into oxalates have contemplated the addition of another compound to the formate. This has required separating the foreign elementfrom the oxalate. which is often difficult, and at best an unsatisfactory and expense-v involving procedure. Moreover it has long been recognized that the temperature of the formate should be raised suddenly. from' about 2200 to 360 or over but not exceeding 440 C.; and many efforts have been made to satisfy this condition, but so far as known. the oxalates produced are insufficient in quantity and contain too large a percentage of carbonate.

Accor( ing to the present invention the forlnate is converted directly into the oxalate without the addition of any foreign compound. in the presence of air` and b v simply and efficiently arrangng and con-.i trolling the heat zones to whici the formate' is subjected 'in order to convert it into the oxalate. The apparatusl of the present inveution conq'nises means for passing the formate through a preliminary heating zolle b v which it is rendered plastic and then subjecting itto heat not greater than :2200 by which the formate is rendered molten. .\t this temperature the formate is stable and there is no liability that it will be converted into carbonate. lla ving slowly raised the temperature of the formate to 2200 C. the liquid formate is then suddenly raised to the temperature necessary to drive olf the molecule of hydrogen. nalnely. to a temperature between 3G00 and 4400 rI`his is done b V spreading the liquid formate thinly over hot surfaces of the requisite lates from formates has been to raise the temperature of the formate from its stable point to the pointl at which it converts into the oxalate so rapidly that its conversion into carbonate will be prevented. According to the present invention the means employed to raise the formate from its stable point to the point at which it converts into the oxalate is such that although the oxal/ate is produced quantitatively the formation of carbonate is almost entirely prevented.

'lhe preferred form of the invention is illustrated in the accomlmnying dra-wings. in whichlfig. 1 is a front elevation of the improved apparatus for converting formates into oxalates: Fig. :Z is a side elevation. partly in section looking from the right. in Fig. 1: and Fig. 3 is a vertical transverse section substantially through the middle of the apparatus shown in Fig. 1.

'l`he formate is passed in a relatively wide and'thin stream through a heated zone by which the temperature of the formate is gradually raised. Passing the formate through this preliminary heating zone renders the formate more or less plastic. rl`he plastic formate is then introduced into a heated receptacle. the temperature of which is sufficient to make the plastic formate liquid. Care is exercised that the temperature of the liquid formate does not exceed 2200 while it remains in the receptacle, or intermediate heating zone. as it may be termed. By preventing the formate from rising to a degree of temperature higher than 220 (l. at this stage of the process. the.

formate is insured against being converted into a carbonate. The liquid formate is now spread upon a.relatively large heated surface by which its temperature is suddenly raised to 3G00 or slightly over. care being exercised that thetemperature of the formate does not exceed 440 C. Uien the formate has been converted into oxalate on the heated surface. it is scraped off as a fine white powder.

\Vhen the steps of the process briey described above are practiced in the apparatus shown in the accompanying drawings, an oxalate. of high percentage is produced. This apparatus comprises means for containing the formate. means for feeding the formate in a wide, relatively vthin stream through the preliminary heating zone, means for liquefying the formate. means for spreading the liquefied formate over thel heated surface by which it is converted into the oxalate. means for removing the oxalate from the heated surface` and means for conveying the powdered oxalate from the apparatus. The formate in powdered or lump form is fed into a hopper supported on the upper part of a framework 6 resting on a table T supporteehy the legs or standards S. The formate is fed into the preliminary heating zone 9 by a feeding device generally indicated h v the reference character 1U. This feeding device 10 comprises a .formate supporting plate 11 which is arcuate in form. 'l`he plate 11 is located below the open lower end or bottom 1*.) of the hopper 3 and supports the supply of formate in the hopper. 'l`he formate passes out of the hopper into the preliminary heating zone through a slot or opening 13 formed between the forward end of the plate 11 and the tianged part l-l of the hopper. This slot extends4 throughout the length of the hop#Y per. lt will be recognized from the form and' size of the slot 13 that the powdered formate passes down through the preliminary heating' zone in a wide relati\'el .'thin `stream.

In order to discharge the formate from the hopper. the plate 11 is reciprocated back and forth under the opening 12. In practice it has been found that a reciprocation of forty times a minute and a range of movement of about one-half linch is sufficient to secure a proper feed of the formate. conditions of operation depending on the nature of the formate treated. the number of reciprocations per minute may be varied and the range of movement may be increased or decreased. The plate 11 is supported for its reciprocatory or oscillatory movements by four arms 15. depending downwardly from hubs 16 secured to a shaft 1T journalled in standards 1H rising from the frame G. The @plate 11 is secured in adjusted position at the lower ends of the arms 15 by check nuts 19; Oscillatory movements areimparted to the shaft 1T by an arm 21 fastened at its up per end to the shaft and having in its lower end a slot Q2 which receives a crank or eccentric pin 23 screwed into an eccentric 24 journalled in a standard'Q supported from the table 7. 'lhe eccentric pin 23 may be adjusted in the eccentric 2l so as to vary the length of oscillation of the shaft 1T and so the length of reciprocation or oscillation of the plate 11. The eccentricl :24 is driven by a sprocket wheel 26 over which passes a chain 27 which is driven by a second sprocket wheel 28 mounted on one end of a hollow shaft Q9. The other end of the hollow shaft 29 carries a gear 3() which meshes with a gear 31 carried by a second hollow shaft 32. The other end of the shaft 32 carries a worm gear 33 which is driven by a worm 34- inounted on a shaft 35. The hollow shafts 29 and 32 are mounted in brackets supported from the table '7. The shaft is journalled in brackets mounted on a shelf 3Gl supported from the table 7. The shaft 35 carries on its outer end a belt-driven pul- Vnder certainbornein mind that the powdered formate is relatively heavy and has a tendency to move. with the pla-te 11. unless something is in its path 0f travel to block it. The plate 11 is shown in` substantially the neutral position. lf it is assumed t-hat the hopper contains tbv powdered formate and that the plate 1l is moved forward. that is. toward the left. viewing Fig. 3. it will be understood that the formate resting on the plate is carried forward with it and that an open space will be formed adjacent to the bottom of the rear side 3S) of the hopper. Into this open space more formate will fall so that as the plate 1l swings rearwardly again. thv formate which had been carried forward with thv plate is prevented from moving rearwardly with the plate and thv formate at thv discharge end 4() of thv plate l1 will fall down into thv chute 20. ly reason of thv relatively rapid movements of thv l'ved plate 1l it will be recognized that a substantially steady stream ot' formate drops down into the heating Zones.

As the formate passes through thv preliminary heating zone 9 in thv chute 2U it becomes plastic. The plastic formate drops into a heated trough 42 in which it is imme diately liquefied. rl`l1e trough 4'.) is provided -with a steam jacket 43. which is supplied with steam in any convenient manner. Sufficient heat rises from tlieitroifglh 42. and also from other sources of htgtprvs. ently to be described` to keep thv preliminary heating zone El at thv requisite tems perature. lu fact. thv whole apparatus bvcomes hot after a short period of use and for this reason all thv parts are made heavy in order to prevent warping. (')nly a small quantity of thv plastic formate l'alls into the trough momentarily and it is imme`A diately converted into the liquid state. rl`he heat of the trough is so regulated that the temperature of the liquefied formate does not rise above 220 The liquid formate is at once taken from the trough 42 and spread upon the heated surface b v which oxalate. This heated surface consists of a hollow cylinder or drum 45 mounted on the hollow shaft 32. The means for depositing the liquid formate on the heated surface of the drum 45 consists of a rapidly rotating splasher 4G whieh may be composed of sheet iron or steel mounted on a shaft 4T journallvd in brackets supported from the table T. The sha-ft 4T is provided with a pulley 4H over which passes a belt 4S) driven by a pulley 5() on the end of the shaft 51 of a motor 5 2. The splasher 46 acts as a scoop to gather up the liquid formate in the bottom of the trough 42 and throw it by centrifugal force upon the revolving surface of" the hot drum 45. At each revolution of the shaft 47 the splasher 4G cleans outthe trough 42 so it is converted into theI upon the drum 45 too thickly to be instantly converted into oxalate. a second drum 54 is provided. the surface of which travels in close proximity to the surface of the drum 45. as clearly shown in Fig. 3. lf the formate on the surface of the drum 45 is so thick that it touches the surface of the drum 54 as it passes through the opening 55 hetween the two drums. the top surface of the material on the drum 45 will adhere to Vthe hot surface of the drum 54 where it is instantly converted into oxalate. The drum 54 is mounted on the hollow shaft :29.

'l`he drums 45 and 54 are provided internally with gas burners 56. the` mixture ot' gas and air heilig Supplied through the hollow shafts 29 and 32. It will be understood that the heating may be done by electricity. oil. powdered coal or otherwise. In order that the heat may be distributed uniformly over the surfaces of the drums 45 and 54. a layer of some granular. refractory material 5T such as tlint or quarta-sand is provided at the bottom of each drum. This granular material. of course. -tends to re-` main in the bottoms of thel drums as they revolve. thereby conveying the heat to the cylindrical surfaces of the drums uniformly. an action which cannot be successfully accomplished b v direct heating. Radiation p vrometers may be -used for registering and thermostats for controlling the outside telnperaturc of the drums. The products of combustion may be conveyed from the apparatus through the pipe 5S. The draught. of the burner in the drinn 54 is controlled by the damper (it). and the draught of the burner in the drum 45 is controlled by the damper 55). I

'lhe drums turlL-in the directions indicated hy the arrows in Fig. 3. The oxal-ate is removed from the drmu 45 by a knifelike scraper ($2 supported onthe upper ends of plungers (S4 pivotally connected at (S5 to levers (3(3 pivoted to the frame of the apparatus at (3T. The free ends of the levers 6G rest on springs (5S surrounding the upper ends of upright rods ('9. The springs 68 serve to press the scraper 62 against the surface of the drum 45 in order to keep it clean. 'lhe pressure of the springs (38 may be regulated by turning the screws 70. 'lhe oxalate is removed from the surface of the upper drum 54 by a knife-like scraper 72 secured in the lower end of plungers T3 working in a beam T4 arranged transversely at. Pressure is ex'v crtpd upon the scraper TQ b v springs T5 surthe top of the apparatus.

rounding rods TG the upperends of which are received iii brackets TT. 'l`lie pi'essure of the springs T5 may be regulated by turning the rods Tfi which are pi'ovided with squared ends TH for that purpose. The scrapers are composed of sonic high speed tool steel and are arranged so that the edges are kept in good scraping coi-iditioii.

The oxalate removed from tbe surfaces of the drums and which is now in powdered form falls into a trough H() in the llower end of which there is a screw conveyor H1 fixed on a shaft H2 liournalled in the frame of the apparatus. ()nc end of the shaft HQ is provided with a screw gear 83 which meshes with a screw nl mounted on one end of the shaft 35. The screw conveyor 81 conveys the powdered oxalate into a receptacle 85 provided with a iemovable part 8G. The guard HT is provided to prevent the oxalate scraped from the upper diiun 54 from falling onto the fioor.

lt will be recognized from the description of the apparatus illustrated in the drawings that this apparatus constitutes an effective means for converting foriiiates into oxalates. ()nl.v small quantities of the formate are subjected to the various heated zones at one time and the heat of these '/.ones is so regulated that there is no opportunit)y for the fornizite to convert into carbonate. Inasmuch. however. as the operation is one of great rapidity. there is a continuous stream of formate passing into the apparatus and a continuous stream of' oxalate passing out of the apparatus. From this it will be reeognized that'according to` the size of the apparatus it may he made of indefinitely great capacity. In practice. there has been produced. with a relatively small apparatus. QU() pounds of oxalate an hour. So far as is known. there is no other apparatus on the mai'lv'et having an efficiency approaching this.

' The novel method of converting foi-mates into oxalatcs described above is made the subject matter of a divisional application filed b v me September 19. 1921. Serial No, .'TilLTi').

lla ving thus described the invention, what is claimed iszl. An apparatus for converting formate into oxalate.comprising a heated chute in which the formate is rendei'ed plastic. a heated receptacle in which the formate is liquefied. means for feeding the forma-te into `the chute and receptacle` a relatively large lieatfedj surfacefon whichhtyhe, formate is converted yintio; oxa'late(r yand "j icentrivfugally" acting 'means for 4seoopirigl the liquid for- A into oxal'ate comprising an open trough-likel receptacle in which thil formate is liquefied. means for heating the receptacle. a traveling surface located beside the receptacle ony which the foiiiiate is converted into oXalate. means for heating the traveling surface. and rotating means adapted to i'einove all the formate from the receptacle at each rotation and deposit it upon the traveling snrface.

l. An apparatus for converting formate into oxalate comprising a receptacle in which the formate is liquefied. means for heating'the receptacle. means for feeding the formate into the receptacle. a -drum loeatedbeside and above the receptacle b v which the liquid formate is converted into oxalate. means for revolving the drinn. means for heating the drum. centrifugallyv acting means for removing the liquid formate from the receptacle and depositing it upon the surface of the drum` and means for removing the oxalate from the drum.

An apparatus` for converting formate into oxalate comprising a heated receptacle i'n which the formate is liquefied. means for feeding the formate to the receptacle` a heated revolving drum located beside the receptacle. a second heated revolving drum located beyond the first one., a revolving paddle for removing the liquid formate from the receptacle and depositing it, upon the surface of the first drum. said drums being kept ata temperature sufiicient to convert the formate deposited upon them `into oxalate. aiid lmeans for removing the oxalate from the drums. d,

An apparatus for /enverting formate into oxalate which comprises a rotating drum. on the surface 'of which the formate is converted into oxalate. means for conveying the formate in a liquid state to the surface of the drum. means for heating the drum consisting of a layer of granular refractory material in the drum. and means for heating the i-efractoi')y material.

.7. An apparatus for converting formate into oxalate comprising a `drum on the surlface rof which the formate is converted into ovalate. means, for rotating the drum, a `layer ofgranular.refractory materialin the drum. means l'or heating:r the refraetory material. means for eonveying the formate to the surl'aee of the drum. and means for removing the oxalate from the drum.

H. .\n apparatus for eonverting formate into oxalate eomprising a heated drum 0n the surfaee of whieh the formate is Converted into oxalate. means for rotating the drum. a heated reeeptaele in whieh the formate is liquefied. means for conveying the formate into the reeeptaele and a revolving paddle for removing the liquid formate from tla` reeeptaele and depositing it upon the drum.

i). .\n apparatus for converting formate. into oxalate eomprising an .internally heated drum on the surfare of whieh the formate is eonverted into oxalate. means for rotating the drum. a heated reeeptaele 1orated beside the drum for liqllefhving the formate. means for feeding the formate t0 the reeeptaele. a revolving paddle in the reeeptaele l'oi removing the liquid formate therefrom and depositing it upon the snrl'aee ol' the drum. and a seraper for removing the oxalate from the drum.

l0. A\n apparatusl for eonverting formate into oxalate eomprising a vertieall)Y arranged ehute in whieh the formate is rendered plas-tie. means for feeding the formate into the ehute. a receptacle loeated below the ehute to receive the plastic formate and liquet'y it. means for heating the receptaele. ar relatively large traveling surface lo eated beside the reeeptaele on which the formate eonverted into oxalate. means for heating the surfaee. and means for removing the liquid formate from the receptacle and spreading it on the surface in thin layers.

1l. An apparatus for eonverting formate into oxalate eomprising a heated reeeptaele, a heated ehute loeated above the reeeptaele. means for feeding formate into the ehute, a rotating drum loeated beside the receptacle and a rotating paddle in the reeeptaele for diseharging the formate from the reeeptaele on to the drum.

1:2. An apparatus for eonverting formate into oxalate eomprising a heated reeeptaele in whieh the formate is liquefied. means for feeding the formate into the reeeptaele. a heated rotating drum` loeated beside the reeeptaele` means for removing the formate from the reeeptaele and depositing it upon the drum, a seeond heated rotating drum loeated in close proximity to the rst drum, and meansl for removing the material from the drums.

HERMAN lV. PAULUS. 

